Tension adjustments for trampolins



Jan. Z0, 1959 R. M. FENNER ETAL 2,869,147

TENSIQNIADJUSTMENTS FOR TRAMPOLINS 2 Sheets-Sheet Filed May 16. 1956 m y A M M Md M M 5W Z Z 5./

Jam 20 1959 R. M. FENNER E'rAL 2,869,147

TENSION ADJUSTMENTS FOR TRAMPoLINs Filed May 1e, 195e' 2 Sheets-Sheet 2 TENSION AniUsrMENrs non 'rinAMroLrNs Robert M. Fenner and Donald E. Hamilton, Denver, Colo.

Application May 16, 1956, Serial No. 585,344

6 Claims. (Cl. 5-202) This invention relates to a trampoln, and more particularly to the trampolins illustrated and described in applicants co-pending applications Serial Nos. 445,668, now Patent No. 2,799,867, granted 'July 23, 1957, and 501,528, now Patent No. 2,809,383, granted October 15, 1957. lt has been found that there is a necessity for means in the bed frame of a trampoln to vary the width and length of the bed frame to adjust the tension in the springs supporting the bed. A new trampoln, as delivered from the factory, will have perfect tension in the bed. However, after use, the bed, the bed springs and the bed frame wi'l undergo a preliminary adjustment which often results in a slackness in the bed which can only be removed with great difficulty. It has also been found that it is desirable to provide a bed which is exceedingly taut for the use of highly skilled artists, and less taut and more resilient for children and beginners.

The principal object of this invention is to provide means in the bed-supporting frame of a trampoln whereby the length and width of the frame can be quickly and easily increased or decreased so as to increase ordecrease the tension in the bed as desired.

Another object of the invention is to so `construct the tension-adiusting means that it can be manipulated by the use of a simpie wrench without dismantling or interfering with the continual use of the trampoln.

A further object is to provide tension adjusting means in the bed-supporting frame of a trampoln which will not weaken the structural strength of the bed frame or allow torsional or bending distortions in the latter frame.

Other objects and advantages residein the detail construction oi" the invention, which is designed for simplicity, economy, and eiciency. These will become more apparent from the following description.

in the following detailed description of the invention, reference is had to the accompanying drawing which forms a part hereof. Like numerals refer to like parts in all views of the drawing and throughout the description. i

In the drawing:

Fig. 1 is a plan view of the bed frame of a trampoln of the type illustrated in applicants co-pending application Serial No. 445,668, now Patent No. 2,799,867, granted July 23, 1957;

Fig. 2 is a fragmentary, enlarged, side elevation of the midportion of the bed-supporting frame of Fig. 1;

Fig. 3 is a bottom View looking upwardly at the side structure of Fig. 2;

Fig. 4 is a cross-section through one side of the frame, taken on the line A11nd, Fig. 2;

Fig. 5 is a fragmentary, enlarged end view looking at one end of the supporting trame of Fig. 1;

Fig. 6 is a bottom view looking upwardly at the end structure of Fig. `5; v

Fig. 7 is an enlarged cross-section, taken on the vline ,7--7, Fig. 5; and

Fig. 8 is a detail, fragmentary, perspective view illustrating an alternate structure for attaching trampoln bed springs to a supporting frame.

In Fig. l the outline oi a conventional trampoln bed has been indicated in broken line at 141 with the conven` tional supporting springs indicated at 11 connected to spring eyes Sti on the supporting frame.

The bed 1@ and its supporting springs 11 are tensioned within a rectangular, tubular surrounding bed frame sup# ported upon U-shaped folding leg members 12 which extend diagonally across the corners of the bed frame and are hingedly mounted at their upper extremities in suit able leg hinge sleeves 13. When the legs are unfolded to the supporting position, the bed frame is braced therefrom by means of suitable leg chains 14 or in any other conventional manner.

The bed 1t?, the springs 11, the leg members 12, the hinge sleeves 13, and the supporting structure are illustrated and described more in detail in applicants said co-pending application Serial No. 445,668, now patent No. 2,799,867, granted luly 23, 1957. The instant application is limited to structures whereby the sides and ends of the rectangular bed frame may be increased or decreased in length for varying the tension in the bed 10 by means or an expanding mechanism positioned at each end and at each side of the bed frame.

The expanding mechanisms at the two sides of the bed frame are illustrated in Figs. 2, 3 and 4 and each employs a main side tube 1S and a brace tube 16 Welded together in parallel relation. An inner frame tube 17 is teiescopically mounted in each extremity of the main tube 15. These inner frame tubes project outwardly from the two extremities oi' the main tube 15 and each is hingedly connected at its outer extremity to a hinge fitting 18. An L-shaped corner traine member 19 is also hingedly connected to each hinge iitting 18 so that it may be swung upwardly and over the tubes 15 and 16 to fold the bed. An inner brace tube Ztl is telescopically mounted in each extremity of the brace tube 16. The outer extremities of the inner brace tubes 2t) are welded to the adjacent inner frame tubes 17, as indicated at 21.

it can therefore be seen that the length of the bed frame can be increased or decreased by sliding the tubes 17 and 2d within the tubes 15 and 16. 1t can also be seen that by the use of two outer and two inner tubes, rotation of the tubes within each other is prevented, so that all torsional stresses are absorbed and twisting of the sides or the bed frame is prevented.

The outward and inward movements of the tubes 17 and 2@ within the tubes 115 and 16 is accomplished by means of a double-threaded side jackscrew 22 having a right-hand thread on one extremity and a left-hand thread on the other extremity. A laterally positioned stub tube 24 is welded belcw'and extends transversely across the tubes i5 and 16. The jackscrew 22 is horizontally and rotatably supported in a jackscrew bearing sleeve 23 which is weldec to the stub tube 24 and extends at its extremities through internally threaded nuts 25 and into screw-receiving tubes 2d. The nuts 25 are Welded or otherwise formed on the extremities of the tubes 26. Each of the Soren/deceiving tubes 26 is welded at its outer extremity to one of the inner frame tubes 17. as indicated at 27 and is supported and braced at its inner extremity by a yoke strap 29 which is welded to and suspended from the tubes 15 and 16 and through which the tube 26 is slidable.

The main side tube 15 is rigidly trussed to prevent bending by means of a tubular truss member 28 which extends from one extremity of the main side tube 15 being of the entire telescoping structure. The leg chains 14 are connected to suitable` connecting eyes 30 on the screw-receiving tubes 26. Longitudinal movement of the jackscrew 22 in the bearing sleeve 23 is prevented by means of welded ilanges 31, and rotation of the jackscrew 22 is accomplished through the medium of a toolreceiving head 32.

It can be seen that if the jackscrew 22, at each side of the bed frame, is rotated in one direction, by means of the wrench engaging the head 32, the two nuts 25 at each side will be forced away from each other, and this movement will be transmitted through the screwreceiving tubes 26 to the inner frame tubes 17 so as to increase the length of the entire bed-supporting frame. If rotated in the other direction, the jackscrews 22 will act through the same members to decrease the length of the bed-supporting frame.

The expanding mechanisms at the two ends of the bed frame are illustrated in Figs. 5, 6 and 7. Each ernploys a straight end frame tube 33 which is braced against bending by means of a truss tube 34. The truss tube 34 is welded at its extremities, as shown at 35, to the extremities of the end frame tube 33, and is spaced in bracing relation to the straight tube by means of truss struts 36. One extremity of each of the adjacent corner frame members 19 telescopically extends into each extremity of the straight tube 33, and it can be seen that if the corner frame members are forced outwardly from the tube 33, the width of the bed frame will be increased and if forced inwardly, the width thereof will be decreased.

This outward and inward movement of the corner frame members 19, at each extremity of the bed frame, is accomplished through the medium of end jackscrews 37. Each end jackscrew 37 is rotatably mounted in a jackscrew sleeve 38 supported below the tubes 33 and 34 upon inclined supporting braces 39. The jackscrews 37 are similar to the previously described jackscrews 22, that is, each is formed with left-hand threads on one extremity and right-hand threads on the other extremity, and the screws are rotatable through the medium of toolengaging heads di) formed thereon. The threaded portions of the jackscrews 37 extend through internally threaded nuts 41 and into tubular screw jackets 42 which are welded to or formed on the nuts 41.

j The screw jackets 42 are rigidly supported through the medium of inclined braces 43 from a pair of sliding sleeves 44 and 4S connected by cross braces 49, the sleeves 44 are slidably mounted on the straight frame tube 33 and thesleeves 45 are slidably mounted on the truss tube 34. A rigid connecting tube d is welded at its one extremity to each of the screw jackets 42, as shown at 47, and to 'each of the corner frame members 19, as shown at 4?.

' It can be seen that the members ed, 45, 52, 46 and 19 move as a unit, an-d these members are moved by rotation of the jackscrew 37. For instance, if the latter screw be rotated in one direction, it will force the screw jackets 42 away from each other, and this outward movement will be communicated through the connecting tubes 46 to the corner frame members 19 to increase the width of the bed frame.

Ylt will be noted that the leg hinge sleeves 13 at one extremity of each leg member 12 are mounted on and welded to the sliding sleeves 4d so that they will move as a unit with the corner members 19 and the leg hinge sleeve 13, at the other extremity of each leg, is welded to the adjacent corner member 19 so nas to move therewith.

An alternate structure for connecting the bed springs 11 to the supporting frame is illustrated in Fig. S to replace the conventional spring eyes G. In the alternate structure, a relatively heavy wire or rod 51 is corrugated to provide a continuous series of oppositely extending loops. The corrugated wire Slis welded at spaced points to the supporting frame tube, as indicated at 52, to provide a continuous series of spring-receiving loops along the frame tube into any of which the springs may be connected.

While a specific form of the improvement has been described and illustrated herein, it is desired to be understood that the same may be varied, within the scope of the appended claims, without departing from the spirit of the invention.

Having thus described the invention, what is claimed and desired secured by Letters Patent is:

l. An expansible trampoln bed-supporting frame comprising: four L-shaped corner members; supporting means mounted on and extending downwardly from and diagonally of each corner member for supporting the latter from a floor; two tubular end frame members; two tubular side frame members, one extremity of each corner member telescopically engaging in one of the side tubular members, and the other extremity of each corner member telescopically engaging in one of the end tubular members; an end expansible means supported from and parallel to each of said two tubular end frame members, each end expansible means being connected at its extremities with the two adjacent corner members; and a side expansible means supported from and parallel to each of said two tubular side frame members, each side expansible means being hingedly connected at its extremities with the two adjacent corner members so that actuation of said two end expansible means will act to vary the width of said frame and actuation of said side expansible means will act to vary the length of said supporting frame.

2. An expansible trampoln bed-supporting frame comprising: four L-shaped corner members; supporting means mounted on and extending downwardly from each corner member and diagonally thereof for supporting the latter from a door; two tubular end frame members; two tubular side frame members, one extremity of each corner member telescopically engaging in one of the side tubular members, and the other extremity of each corner member telescopically engaging in one of the end tubular members; an end bearing sleeve mounted on and in parallel, spaced relation with each tubular end frame member; a side bearing sleeve mounted on and in parallel, spaced relation with each tubular side frame member; an internally threaded nut member mounted on each extremity of each corner member in axial alignment with said end and side bearing sleeves; an end jack screw rotatably mounted at its middle in each end bearing sleeve; a side jack screw rotatably mounted in each side bearing sleeve, said jack screws having oppositely threaded extremities extending into the nut members of the adjacent corner members; and means on each jack screw acting to prevent longitudinal movement thereof in its bearing sleeve, so that rotation of said end jack screws will act to vary the width of said frame, and rotation of said side jack screws will act to vary the length of said frame.

3. A laterally expansible, bed-supporting frame for trampolins comprising: two side frame structures; an L- shaped corner member mounted at each extremity of each side frame structure; means mounted on and extending downwardly from each corner member for supporting the latter from the door; a straight end frame tube at each extremity of said supporting frame, the L-shaped end members at each extremity of the side frame members telescopically engaging in opposite ends of said straight end frame tubes; a bearing sleeve supported from and in parallel, spaced relation with each straight end frame tube; a jackscrew extending through each bearing sleeve, each jackscrew having threads of opposite hand upon .its opposite extremities; a nut mounted on each threaded extremity of each jackscrew; a tubular screw jacket rigidly formed on each nut and surrounding said jackscrew; arconnecting member extending from each screw jacket to an adjacent corner frame member to transmit 4 the axial movement of said nuts to said corner frame members; and means for slidably supporting said screw jackets from said end frame tube.

4. A longitudinally expansible trampoln bed-supporting frame comprising: two end frame structures; an L- shaped corner member supported from each extremity of each end frame structure; a main side tube at each side of said supporting frame; an inner frame tube telescopically mounted in each extremity of each main side tube; hinge means connecting each inner frame tube to one of said corner frame members; a bearing sleeve supported from and in parallel, spaced relation with each main side tube; a jack screw rotatably extending through each bearing sleeve and being provided with threads of opposite hand at its extremities; a nut mounted on each extremity of each jack screw; and a screw-receiving tube formed at its one extremity integrally with each nut and surrounding one extremity of said jack screw, said screwreceiving tube being secured at its other extremity to the adjacent inner frame tube so that longitudinal movement of the nut thereon will be transmitted to the inner trame tube for increasing the length of said bed-supporting frame.

5. A longitudinally expansible trampoln bed-supporting frame as described in claim 4 having means for rotatably and slidably supporting said screw-receiving tubes from said main side tubes.

6. A longitudinally expansible trampoln bed-supporting frame as described in claim 5 having an outer brace tube secured in parallel relation to each main side tube; an inner brace tube telescopically mounted in and projecting from each extremity of each outer brace tube; and means securing the projecting extremity of each inner brace tube to the adjacent inner frame tube so that the connected inner tubes will move as a unit.

References Cited in the tile of this patent UNITED STATES PATENTS Re. 19,272 Kurkchee Aug. 14, 1934 223,017 Tucker et al. Dec. 30, 1879 272,077 Mueller Feb. 13, 1883 689,240 Sprague Dec. 17, 1901 1,080,577 Pascale Dec. 9, 1913 1,259,022 Kean Mar. l2, 1918 2,534,019 Griswold Dec. 12, 1950 2,641,777 Karasek June 16, 1953 

